Hull stern



Aug. 14, 1951 I P. CARLOTTI 2,564,560

HULL STERN Filed June 4, 1949 3 Sheets-Sheet 1 I N V EN TOR. P/ERAE CARL or 7/ P. CARLOTTI Aug. 14, 1951 HULL STERN Filed June 4, 1949 3 Sheets-Sheet 2 ATTORNEY 1951' P. CARLOTTI 2,564,560

HULL STERN Filed June 4, 1949 3 Sheets-Sheet 5 INVENTOR. PIE/PIPE C/mwrr/ ATTORNEY Patented Aug. 14, 1951 Pierre Carlotti, Paria France, assignor of one-half to Socit des Ateliers et Chantiers de France,

Paris, France Application June 4, 1949, Serial No. 97,128 :In France September 4, 1948.

This invention relates to the construction of ship hull stems and is more particularly concerned with ship hull sterns which reduce the power necessary-to overcome the resistance to forward movement of the hull.

My copending application, Serial No. 788,560, dated November 18,1947, also relates to ship hull sternsand has for its object the provision of an improved stern structure. The ship stern comprises an appendage which has various characteristics which have the effect of placing the screw, the screw carrier and the rudder substantially outside the boundary zone surround 2 Claims; (01. 114-57) ing the ship hull. This appendage lies in the symmetry plane of the ship and comprises a leading edge disposed at an angle of 60 to 90 with respect to the tangent plane of the hull which it meets at a point above the plane of the hull bottom. The perpendicular portions I of the appendage in relation to the symmetry plane of the ship are of hairpin form with two long branches which are substantially rectangular and vertical and the planes tangent to the appendage at its junction to the hull are substantially perpendicular to the tangent planes of the hull at the same point. The outline of the appendage shows a straight portion situated in an extension of the base of the hull and the rear edge of the appendage is formed by two straight lines defining between them an obtuse angle, the apex of which bisects the shaft of the screw.

In the case of a ship with twin screws, the appendage comprises a thick horizontal wing perpendicular to the lateral faces of the central appendage, having sleeves at its two extremities which form bearings for the propeller shafts. The leading edges of the wing and the sleeves are disposed at a substantial distance from the side of the hull.

It is the object of the present invention to provide an improved hull structure which reduces the power necessary to overcome the resistance to forward movement to an even greater degree than that possible by the structure disclosed in my said copending application.

In accordance with the present invention I provide a ship stern structure comprising an.

appendage of the type above described in combination with a distributor, and also advantageously with a rectifying rudder, the distributor being formed integrally with the appendage, which is suitably modified in form to, provide it with distributing surfaces, or being in the form of a separate appendage combined with the first- ;mentioned appendage. The said appendage, distributor and rectifier rudder have, in one embodiment of the invention, a form similar to the thick portion of an airplane wing with the free edges tapered or rounded. This is also similar in form to the appendage described in my copending application Serial No. 788,560 but having its rear portion reduced to a helical shape so that its transverse sections instead of having an elongated or flattened ellipsoidal form have, as they approach the extremity of the appendage, a form closely similar in structure to that of the sections taken transversely and successively in a portion of a blade of an airplane screw. The modified form of the appendage is, of course,

made in the direction corresponding to the direction of rotation of the screw of the vessel with which it is associated.

The combination of astern as above described with one or more distributor surfaces and advantageously also with a rectifying rudder has the advantage over known distributors and rectifiers that the whirling field provided by the arrangement of the invention is developed outside the turbulent bounds of the hull and not inside this zone, so that the efliciency of the structure is sufiiciently increased.

Other objects and features of the invention will be readily apparent from the following detailed description of an illustrative embodiment of the invention with particular reference to the drawings wherein Fig. 1 is a side elevational view of the aft portion of a ship embodying features of the invention;

Fig. 2 is a plan view of the structure shown in Fig. 1, and

Fig. 3 is an end elevation of the structure shown in Figs. 1 and 2.

Referring to the drawings, the reference numeral l0 designates generally the hull stern portion of a ship having a longitudinally extending body portion of square cross-section and having a generally fiat bottom II and vertically extending sides. The hull stern portion l0 extends upwardly, inwardly and aft from the bottom and sides, respectively, of the middle body portion of the ship at an approximately constant rate for a substantial portion of the length of the hull. There is thereby provided a generally uniform convex surface l2 throughout the entire stern. As shown in Figs. 1-3, the hull stern ll has a vertical fin l3 housing a propeller shaft I4 and afflxed to the stern l0 along the curved convex surface I2 and extending forwardly from a point forward of the rear end of the stem to a point aft of the fiat bottom H. The fin I3 is formed of vertical, semi-lenticular transverse cross-sections throughout its length and the bottom I4 of the fin i3 lies in the generally horizontal plane of the fiat bottom portion ll of the hull ID. The forward end l5 of the fin I3 is formed o nrorisle a erall ra gh e ge which extends upwardly and forwardly from the bottom M of the fin and meets the convex surface l2 of the hull at an angle within the range I of 60 to 90. The rear end of the fin is formed to provide two edges each of which is curved transversely and in reverse respective directions. The curves meet at the axis of thepropeller shaft i6 and afford curved approach paths of water flow to a propeller I! mounted on the propeller shaft [6. More particularly, as shown in gigs, l to 3, each rear edge of the fin I3 is generally straight in the fore and aft direction and slopes aft to meet along the aggis of the propeller shaft l6,

While my invention is thus for purposes of illustration embodied in a single screw ship, it will be obvious that my stern construction may also lee-embodied multiple screw vessels, e; g. ;wi n screw, vessels. It will also be obvious to those skilled in the art that various changes and modifications may be made in the specific embodiment above-described and illustrated in the accompanying drawings without departingfrom the scope of'myinvention as defined in the @PEQ ded claims, and it is intended, therefore, that all matter contained in the foregoing description and the drawings shall be inter: preted as illustrative only and not as limiting the invention.

What I claim is:

1, In a ship having a longitudinallyextend? ing body portion of square cross-section including a generally fiat bottom and vertically extends ing sides, stern portion extending upwardly, inwardly, and aft from the bottom and sides, respectively, of the middle body portion at an approximately constant rate for a substantial portion of the length of the hull thereby providing a generally uniform convex surface throughout the entire the improvement comprisinga hull stern, a vertical fin housing a propeller shaft affixed to the stern along the curved surface and extending forwardly from a point forward of the rear end of the stern to a point aft of the fiat bottom, said fin formed of vertical semi-lenticular transverse cross-sections throughout its len t and. he bo thereof ly n n t e n rl y hor z n a plane f he a e tqm. portion of the hull, the forward end of said fin formed to provide a generally straight edge, said edge extending upwardly and forwardly from the bottom of the fin and meeting the convex surface at angle within the range of from to 3Q, the rear of said fin formed to provide two edges, each rear edge being curved transverselyand in reverse respective directions and said curves meeting at the axis of the propeller shaft to afford curved approach paths of water flow to a propeller mounted on said shaft.

2. The structure as claimed in claim 1 wherein ea h rear ed e s ne ally st ai ht. the fo nd. ft dire ion nd a h sai rear d e lenins, a t o mee a one th ax of he more; shaft. c

smear. CAM-0TB;

BEFEB QE C TED The following r f nces are of record in the file o th a ent:

Modern Shipfitters Handbook, W. E. wans0n, 2m ee =pub1 ish d ma, age by Cornel time Bras N w Yeri- 

